An OH radical detection probe (102) includes an aromatic carboxylic acid, a polar aprotic organic solvent, and a polar protic organic solvent.

Gas analyzer and method for measuring nitrogen oxides in an exhaust gas, wherein to measure the nitrogen oxides, ozone is generated from oxygen, the exhaust gas is treated with the ozone generated to convert nitrogen monoxide within the exhaust gas into nitrogen dioxide, the nitrogen dioxide concentration in the treated exhaust gas is measured photometrically using a first light-emitting diode which emits with a central wavelength between 350 nm and 500 nm and output as the nitrogen oxide concentration in the exhaust gas, and the ozone concentration in the treated exhaust gas is measured photometrically using a second light-emitting diode which emits with a central wavelength between 250 nm and 265 nm, where generation of the ozone using the measured ozone concentration as an actual value is regulated to a prespecified setpoint value to enable reliable continuous measurement of nitrogen oxides in exhaust gases with a low outlay on equipment.

The present invention is one that accurately measures an exhaust gas component regardless of variation in atmospheric pressure around a test object that is a vehicle or part of it, and an exhaust gas analysis apparatus that measures component concentration in exhaust gas discharged from the test object that is the vehicle or part of it. The exhaust gas analysis apparatus includes: an exhaust gas detector that mixes the exhaust gas and reactive gas together and detects the resulting phenomenon; a pressure gauge that measures the atmospheric pressure at the time of measurement of the exhaust gas or pressure at a predetermined point inside the exhaust gas analysis apparatus as measured pressure; and a correction part that, on the basis of the measured pressure by the pressure gauge, corrects the measurement error of the exhaust gas detector associated with a variation in the supply amount of the reactive gas.

A gas measuring device includes: a filter to which a power supply that applies a voltage or current is connected, which generates resistance heat, and which combusts a predetermined combustible gas in contact therewith; and a gas sensor configured to detect the combustible gas that has passed through the filter.

The present disclosure is directed to a selective multi-gas sensor device that detects when a high concentration level of a particular gas, such as methane, carbon monoxide, and/or ethanol, is present. The selective multi-gas sensor device detects and identifies a particular gas based on a ratio between a sensitivity of a gas sensitive material at a first temperature and a sensitivity of the gas sensitive material at a second temperature.

An apparatus includes: a gas maintenance system having a gas supply system fluidly connected to one or more gas discharge chambers; a detection apparatus fluidly connected to each gas discharge chamber; and a control system connected to the gas maintenance system and the detection apparatus. The detection apparatus includes: a vessel defining a reaction cavity that houses a metal oxide and is fluidly connected to the gas discharge chamber for receiving mixed gas including fluorine from the gas discharge chamber in the reaction cavity, the vessel enabling a reaction between the fluorine of the received mixed gas and the metal oxide to form a new gas mixture including oxygen; and an oxygen sensor fluidly connected to the new gas mixture to sense an amount of oxygen within the new gas mixture. The control system is configured to estimate a concentration of fluorine in the received mixed gas.

A system for detecting an analyte gas in an environment includes a first gas sensor, a first contaminant sensor separate and spaced from the first gas sensor, and electronic circuitry in electrical connection with the first gas sensor to determine if the analyte gas is present based on a response of the first gas sensor. The electronic circuitry is further in electrical connection with the first contaminant sensor to measure a response of the first contaminant sensor over time. The measured response of the first contaminant sensor varies with an amount of one or more contaminants to which the system has been exposed in the environment over time.

The present invention relates to a method (1) for determining a content of H.sub.2S in a process gas comprising H.sub.2S. The method (1) comprises extracting (2) a sample of the process gas, performing oxidation (4) of at least a major portion of H.sub.2S of the sample, whereby oxidation products comprising elemental sulfur are formed, analysing (6) the oxidized sample by optical absorption spectroscopy at wavelengths above 310 nm, and determining (8) the content of H.sub.2S in the process gas based on the analysing. The invention further relates to a system (100) for determining a content of H.sub.2S in a process gas comprising H.sub.2S, and use of system (100).

In various embodiments, rapid, sensitive detection of molecular hydrogen is achieved by receiving sample gas that includes ambient water vapor and hydrogen, passing the sample gas through a gas dryer, chemically converting hydrogen in the sample gas to water vapor to produce converted sample gas, measuring water vapor in the converted sample gas to produce a water vapor signal, separating the water vapor signal in the time domain into an ambient water vapor signal and a hydrogen-derived water vapor signal, wherein the gas dryer dampens variation in the ambient water vapor signal, and outputting a hydrogen signal that describes molecular hydrogen in the sample gas that is based on the hydrogen-derived water vapor signal.

In various embodiments, rapid, sensitive detection of molecular hydrogen is achieved by receiving sample gas that includes ambient water vapor and hydrogen, passing the sample gas through a gas dryer, chemically converting hydrogen in the sample gas to water vapor to produce converted sample gas, measuring water vapor in the converted sample gas to produce a water vapor signal, separating the water vapor signal in the time domain into an ambient water vapor signal and a hydrogen-derived water vapor signal, wherein the gas dryer dampens variation in the ambient water vapor signal, and outputting a hydrogen signal that describes molecular hydrogen in the sample gas that is based on the hydrogen-derived water vapor signal.